1 // Copyright 2012 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
9 #if V8_TARGET_ARCH_MIPS
11 #include "src/codegen.h"
12 #include "src/debug.h"
17 bool BreakLocationIterator::IsDebugBreakAtReturn() {
18 return Debug::IsDebugBreakAtReturn(rinfo());
22 void BreakLocationIterator::SetDebugBreakAtReturn() {
23 // Mips return sequence:
30 // nop (in branch delay slot)
32 // Make sure this constant matches the number if instrucntions we emit.
33 DCHECK(Assembler::kJSReturnSequenceInstructions == 7);
34 CodePatcher patcher(rinfo()->pc(), Assembler::kJSReturnSequenceInstructions);
35 // li and Call pseudo-instructions emit two instructions each.
36 patcher.masm()->li(v8::internal::t9, Operand(reinterpret_cast<int32_t>(
37 debug_info_->GetIsolate()->builtins()->Return_DebugBreak()->entry())));
38 patcher.masm()->Call(v8::internal::t9);
39 patcher.masm()->nop();
40 patcher.masm()->nop();
41 patcher.masm()->nop();
43 // TODO(mips): Open issue about using breakpoint instruction instead of nops.
44 // patcher.masm()->bkpt(0);
48 // Restore the JS frame exit code.
49 void BreakLocationIterator::ClearDebugBreakAtReturn() {
50 rinfo()->PatchCode(original_rinfo()->pc(),
51 Assembler::kJSReturnSequenceInstructions);
55 // A debug break in the exit code is identified by the JS frame exit code
56 // having been patched with li/call psuedo-instrunction (liu/ori/jalr).
57 bool Debug::IsDebugBreakAtReturn(RelocInfo* rinfo) {
58 DCHECK(RelocInfo::IsJSReturn(rinfo->rmode()));
59 return rinfo->IsPatchedReturnSequence();
63 bool BreakLocationIterator::IsDebugBreakAtSlot() {
64 DCHECK(IsDebugBreakSlot());
65 // Check whether the debug break slot instructions have been patched.
66 return rinfo()->IsPatchedDebugBreakSlotSequence();
70 void BreakLocationIterator::SetDebugBreakAtSlot() {
71 DCHECK(IsDebugBreakSlot());
72 // Patch the code changing the debug break slot code from:
73 // nop(DEBUG_BREAK_NOP) - nop(1) is sll(zero_reg, zero_reg, 1)
74 // nop(DEBUG_BREAK_NOP)
75 // nop(DEBUG_BREAK_NOP)
76 // nop(DEBUG_BREAK_NOP)
77 // to a call to the debug break slot code.
78 // li t9, address (lui t9 / ori t9 instruction pair)
79 // call t9 (jalr t9 / nop instruction pair)
80 CodePatcher patcher(rinfo()->pc(), Assembler::kDebugBreakSlotInstructions);
81 patcher.masm()->li(v8::internal::t9, Operand(reinterpret_cast<int32_t>(
82 debug_info_->GetIsolate()->builtins()->Slot_DebugBreak()->entry())));
83 patcher.masm()->Call(v8::internal::t9);
87 void BreakLocationIterator::ClearDebugBreakAtSlot() {
88 DCHECK(IsDebugBreakSlot());
89 rinfo()->PatchCode(original_rinfo()->pc(),
90 Assembler::kDebugBreakSlotInstructions);
94 #define __ ACCESS_MASM(masm)
98 static void Generate_DebugBreakCallHelper(MacroAssembler* masm,
100 RegList non_object_regs) {
102 FrameScope scope(masm, StackFrame::INTERNAL);
104 // Load padding words on stack.
105 __ li(at, Operand(Smi::FromInt(LiveEdit::kFramePaddingValue)));
107 Operand(kPointerSize * LiveEdit::kFramePaddingInitialSize));
108 for (int i = LiveEdit::kFramePaddingInitialSize - 1; i >= 0; i--) {
109 __ sw(at, MemOperand(sp, kPointerSize * i));
111 __ li(at, Operand(Smi::FromInt(LiveEdit::kFramePaddingInitialSize)));
114 // Store the registers containing live values on the expression stack to
115 // make sure that these are correctly updated during GC. Non object values
116 // are stored as a smi causing it to be untouched by GC.
117 DCHECK((object_regs & ~kJSCallerSaved) == 0);
118 DCHECK((non_object_regs & ~kJSCallerSaved) == 0);
119 DCHECK((object_regs & non_object_regs) == 0);
120 if ((object_regs | non_object_regs) != 0) {
121 for (int i = 0; i < kNumJSCallerSaved; i++) {
122 int r = JSCallerSavedCode(i);
123 Register reg = { r };
124 if ((non_object_regs & (1 << r)) != 0) {
125 if (FLAG_debug_code) {
126 __ And(at, reg, 0xc0000000);
127 __ Assert(eq, kUnableToEncodeValueAsSmi, at, Operand(zero_reg));
129 __ sll(reg, reg, kSmiTagSize);
132 __ MultiPush(object_regs | non_object_regs);
136 __ RecordComment("// Calling from debug break to runtime - come in - over");
138 __ PrepareCEntryArgs(0); // No arguments.
139 __ PrepareCEntryFunction(ExternalReference::debug_break(masm->isolate()));
141 CEntryStub ceb(masm->isolate(), 1);
144 // Restore the register values from the expression stack.
145 if ((object_regs | non_object_regs) != 0) {
146 __ MultiPop(object_regs | non_object_regs);
147 for (int i = 0; i < kNumJSCallerSaved; i++) {
148 int r = JSCallerSavedCode(i);
149 Register reg = { r };
150 if ((non_object_regs & (1 << r)) != 0) {
151 __ srl(reg, reg, kSmiTagSize);
153 if (FLAG_debug_code &&
154 (((object_regs |non_object_regs) & (1 << r)) == 0)) {
155 __ li(reg, kDebugZapValue);
160 // Don't bother removing padding bytes pushed on the stack
161 // as the frame is going to be restored right away.
163 // Leave the internal frame.
166 // Now that the break point has been handled, resume normal execution by
167 // jumping to the target address intended by the caller and that was
168 // overwritten by the address of DebugBreakXXX.
169 ExternalReference after_break_target =
170 ExternalReference::debug_after_break_target_address(masm->isolate());
171 __ li(t9, Operand(after_break_target));
172 __ lw(t9, MemOperand(t9));
177 void DebugCodegen::GenerateCallICStubDebugBreak(MacroAssembler* masm) {
178 // Register state for CallICStub
179 // ----------- S t a t e -------------
181 // -- a3 : slot in feedback array (smi)
182 // -----------------------------------
183 Generate_DebugBreakCallHelper(masm, a1.bit() | a3.bit(), 0);
187 void DebugCodegen::GenerateLoadICDebugBreak(MacroAssembler* masm) {
188 Register receiver = LoadDescriptor::ReceiverRegister();
189 Register name = LoadDescriptor::NameRegister();
190 RegList regs = receiver.bit() | name.bit();
191 if (FLAG_vector_ics) {
192 regs |= VectorLoadICTrampolineDescriptor::SlotRegister().bit();
194 Generate_DebugBreakCallHelper(masm, regs, 0);
198 void DebugCodegen::GenerateStoreICDebugBreak(MacroAssembler* masm) {
199 // Calling convention for IC store (from ic-mips.cc).
200 Register receiver = StoreDescriptor::ReceiverRegister();
201 Register name = StoreDescriptor::NameRegister();
202 Register value = StoreDescriptor::ValueRegister();
203 Generate_DebugBreakCallHelper(
204 masm, receiver.bit() | name.bit() | value.bit(), 0);
208 void DebugCodegen::GenerateKeyedLoadICDebugBreak(MacroAssembler* masm) {
209 // Calling convention for keyed IC load (from ic-mips.cc).
210 GenerateLoadICDebugBreak(masm);
214 void DebugCodegen::GenerateKeyedStoreICDebugBreak(MacroAssembler* masm) {
215 // Calling convention for IC keyed store call (from ic-mips.cc).
216 Register receiver = StoreDescriptor::ReceiverRegister();
217 Register name = StoreDescriptor::NameRegister();
218 Register value = StoreDescriptor::ValueRegister();
219 Generate_DebugBreakCallHelper(
220 masm, receiver.bit() | name.bit() | value.bit(), 0);
224 void DebugCodegen::GenerateCompareNilICDebugBreak(MacroAssembler* masm) {
225 // Register state for CompareNil IC
226 // ----------- S t a t e -------------
228 // -----------------------------------
229 Generate_DebugBreakCallHelper(masm, a0.bit(), 0);
233 void DebugCodegen::GenerateReturnDebugBreak(MacroAssembler* masm) {
234 // In places other than IC call sites it is expected that v0 is TOS which
235 // is an object - this is not generally the case so this should be used with
237 Generate_DebugBreakCallHelper(masm, v0.bit(), 0);
241 void DebugCodegen::GenerateCallFunctionStubDebugBreak(MacroAssembler* masm) {
242 // Register state for CallFunctionStub (from code-stubs-mips.cc).
243 // ----------- S t a t e -------------
245 // -----------------------------------
246 Generate_DebugBreakCallHelper(masm, a1.bit(), 0);
250 void DebugCodegen::GenerateCallConstructStubDebugBreak(MacroAssembler* masm) {
251 // Calling convention for CallConstructStub (from code-stubs-mips.cc).
252 // ----------- S t a t e -------------
253 // -- a0 : number of arguments (not smi)
254 // -- a1 : constructor function
255 // -----------------------------------
256 Generate_DebugBreakCallHelper(masm, a1.bit() , a0.bit());
260 void DebugCodegen::GenerateCallConstructStubRecordDebugBreak(
261 MacroAssembler* masm) {
262 // Calling convention for CallConstructStub (from code-stubs-mips.cc).
263 // ----------- S t a t e -------------
264 // -- a0 : number of arguments (not smi)
265 // -- a1 : constructor function
266 // -- a2 : feedback array
267 // -- a3 : feedback slot (smi)
268 // -----------------------------------
269 Generate_DebugBreakCallHelper(masm, a1.bit() | a2.bit() | a3.bit(), a0.bit());
273 void DebugCodegen::GenerateSlot(MacroAssembler* masm) {
274 // Generate enough nop's to make space for a call instruction. Avoid emitting
275 // the trampoline pool in the debug break slot code.
276 Assembler::BlockTrampolinePoolScope block_trampoline_pool(masm);
277 Label check_codesize;
278 __ bind(&check_codesize);
279 __ RecordDebugBreakSlot();
280 for (int i = 0; i < Assembler::kDebugBreakSlotInstructions; i++) {
281 __ nop(MacroAssembler::DEBUG_BREAK_NOP);
283 DCHECK_EQ(Assembler::kDebugBreakSlotInstructions,
284 masm->InstructionsGeneratedSince(&check_codesize));
288 void DebugCodegen::GenerateSlotDebugBreak(MacroAssembler* masm) {
289 // In the places where a debug break slot is inserted no registers can contain
291 Generate_DebugBreakCallHelper(masm, 0, 0);
295 void DebugCodegen::GeneratePlainReturnLiveEdit(MacroAssembler* masm) {
300 void DebugCodegen::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
301 ExternalReference restarter_frame_function_slot =
302 ExternalReference::debug_restarter_frame_function_pointer_address(
304 __ li(at, Operand(restarter_frame_function_slot));
305 __ sw(zero_reg, MemOperand(at, 0));
307 // We do not know our frame height, but set sp based on fp.
308 __ Subu(sp, fp, Operand(kPointerSize));
310 __ Pop(ra, fp, a1); // Return address, Frame, Function.
312 // Load context from the function.
313 __ lw(cp, FieldMemOperand(a1, JSFunction::kContextOffset));
315 // Get function code.
316 __ lw(at, FieldMemOperand(a1, JSFunction::kSharedFunctionInfoOffset));
317 __ lw(at, FieldMemOperand(at, SharedFunctionInfo::kCodeOffset));
318 __ Addu(t9, at, Operand(Code::kHeaderSize - kHeapObjectTag));
320 // Re-run JSFunction, a1 is function, cp is context.
325 const bool LiveEdit::kFrameDropperSupported = true;
329 } } // namespace v8::internal
331 #endif // V8_TARGET_ARCH_MIPS